Quality control standards within the automotive industry continue to become more stringent. Concurrent goals of the industry are to improve vehicle paint finishes, reduce the weight of vehicles, and to simplify and reduce the cost of assembly and manufacturing procedures. One of the means to achieve these goals has been to produce more and more automotive body panels from fiberglass, plastic or composite materials.
Presently, automotive manufacturers are considering producing trunk lids or deck lids for vehicles from fiberglass based sheet molding compounds (SMC) or like plastic composite materials. Deck lids are almost universally carried by a pair of hinges which are attached to the vehicle body structure beneath the rear window. Generally, each of the hinges has a counterbalancing spring which forces the deck lid to a fully open position once the rear trunk latch is released. Deck lids are generally cantilevered from the hinges with the the latch for the deck lid a considerably distance from the pivot of the hinges.
During the first stage of the painting process, the entire vehicle body including the deck lid and hinges is coated with a primer surface during what is known as an E-coat process. The temperature of the E-coat bath is relatively high, usually in the range of about 325.degree. to 450.degree. F. The deck lid latch mechanism is not installed until after the completion of the painting process. During the E-coat process, the preferred method is to position the deck lid in a partially open position. The present procedure is to hold the deck lid partially down with a hook implement, against the force of hinge springs. One end of the hook is attached to the rear of the deck lid near where the latch mechanism would be installed, and the other end of the hook to the lower rear edge of trunk opening of the vehicle body. Since the hinge springs are designed to force the deck lid to an open position, this method of holding the deck lid in the partially open position causes a bending moment on the cantilevered deck lid. As a result, the extreme heat of the E-coat oven and the bending stress caused by the present positioning method tend to warp the fiberglass or plastic deck lid panels.
As the vehicle body passes through the base and clear coat stages of the painting process, the deck lid is preferably re-oriented into an almost fully closed position flush with vehicle body. The current method is again to use a simple hook at the latch point to hold the deck lid in an almost closed position from the inside while the vehicle body passes through the spray booths which apply the finish coats. Again, as a result the warpage which occurs during the E-coat process is enhanced by the continued stress on the deck lid panel and becomes a highly visible coating defect after the smooth and glossy paint finish has been applied. The warpage may also cause misalignment between the deck lid and the vehicle body structure around the trunk opening.
Because of these problems, automotive manufacturers have been extremely reluctant to use fiberglass or plastic composite deck lid panels, especially on upscale or luxury type vehicles, because of the poor quality fit and finish caused by the aforementioned fixturing problems. In accordance with the present invention it has been discovered that what is needed is an improved fixturing method and apparatus that will eliminate the bending stresses exerted on the fiberglass deck lid during E-coat and various paint or other vehicle body coating applications and yet permit the deck lid to be securely held and easily sequentially oriented to fully open, partially open and almost closed positions.